A single engine failure on a multi-engine aircraft, such as a helicopter, may require immediate corrective measures to be applied by the pilot, copilot and/or autopilot. For instance, commonly-owned U.S. Pat. No. 4,500,966 discloses super contingency aircraft engine control in response to an engine failure.
Waiting for engine speed to drop below ground idle speed before signaling an engine failure may take up to four or five seconds. This results in an excessive delay in applying corrective action. On the other hand, increased sensitivity may result in decreased veracity. False indications of engine failure are also undesirable.